1. Field of the Invention
This invention relates to improvements in an airbag restraint system for protecting a vehicle passenger in a vehicle collision or the like, and more particularly to an airbag which is provided thereinside with suspension belts to prevent the airbag from inflating generally in one direction upon being supplied with gas from a gas generator.
2. Description of the Prior Art
Hitherto a variety of airbag restraint systems for automotive vehicles have been proposed and put into practical use in order to protect a vehicle passenger in the event of a vehicle collision or the like. Such airbag restraint systems are disclosed, for example, in Japanese Patent Publication No. 56-43890 and Japanese Utility Model Provisional Publication No. 54-69543.
The airbag restraint systems are usually arranged as set forth below. The airbag restraint system includes an airbag which momentarily inflates upon being filled with gas from a gas generator in the event of a vehicle collision or the like. The airbag is constituted of front and rear side sheet members which are formed of cloth material. The front and rear side sheet members are sewed at their peripheral portions with each other thereby to be formed into the bag-shape. The rear side sheet member is formed at its central part with a gas inlet through which the gas from the gas generator is supplied into the airbag.
Additionally, the airbag is provided thereinside with a plurality of suspension belts for the purpose of preventing the airbag from inflating to project generally in one direction or toward a vehicle passenger during inflation of the airbag upon being supplied with the gas. Each suspension belt is sewed at its front end section to a front belt catch member which is in turn sewed to the front side sheet member. The rear end section of the suspension belt is sewed to a rear belt catch member which is in turn sewed to the rear side sheet member. The rear side sheet member together with the rear belt catch member is put and tightly secured between a retainer and a base plate which is fixed to an instrument panel or the like in the vehicle.
However, drawbacks have been encountered in such a conventional airbag restraint system, as discussed hereinafter with reference to FIG. 7 of the drawings of the present application. As shown in FIG. 7, the rear end section 1a of each suspension belt 1 is sewed to the rear belt catch member 2 in such a manner that the lengthwise direction of the suspension belt end section 1a is parallel with the direction of a vertical grain of a woven cloth forming part of the rear side sheet member 3. It will be understood that there is a possibility that the rear side sheet member 3 is torn along a sewed section 4 through which the rear belt catch member 2 is sewed to the rear side sheet member 3, when a high tension or impact load is momentarily applied to each suspension belt 1. This considerably lowers a strength in pressure proof of the rear side sheet member 3, thereby causing the rear belt catch member 2 to be torn from the rear side sheet member 3. As a result, the airbag will strike against the vehicle passenger, thus lowering the safety of the conventional airbag restraint system.